Four-hour Layover in Milan Enough Time?

It is reasonable, a quick reasonable. I think I remember that the Duomo is only two, maybe three, from Centrale, so that is fairly quick. Probably be at the Duomo is 30 minutes. Same on return. The only issue might be line for the checked luggage.

Are the luggage hold areas really busy? I'd be stressed if we got back to Centrale and had to wait in line for a long time. I know there's no way to really predict, but are there normally long lines to pick up held luggage?

The Duomo is just 4 stops up on the metro via the yellow line (less than 10 minutes riding the metro with maybe 5 minutes waiting for a train). The metro exit pops up right in the square directly in front of the Duomo (if you use google street view you'll see what I mean).

Right on the same square you'll see the Galleria Vittorio Emanuele II that has lots of places where you could have lunch. There are sit down restaurants but also several places to grab a quick bite. Rick's book on Italy has some recommendations for restaurants with a view of the Duomo.

I think (and maybe someone else can confirm) that there is a taxi stand right in front of/near the Duomo also. Rome2rio.com indicates its a 5 minute taxi ride to Girabaldi Station. You could also take the Metro instead (just reverse your steps back up the 4 stops on the metro and switch to the green line and go up two stops to Giribaldi (that way you could leave your bags at the Central station and pick them up on your way to Girabaldi before you switch lines).

4 hours should be fine. I tried to do the same in 2 hours with not so great results.... I missed my train by 1 minute and got to watch it leave the station without me!

There is a fancy department store next to the duomo that has a food court on the top floor, prices are reasonable, plus you can browse for gourmet goodies.

From 11 a.m. to 4 p.m. you have 5 hours total. If time runs short, lunch can mean picking up a sandwich to go. If you're catching a departing TGV to Paris, then that is obviously a train that cannot be missed, with no later service on the same day.

We are catching the TGV to Paris so I really don't want to miss it and have the same experience that Angela had. :^(

I made a mistake when I first posted, too. Our train from Rome gets into Milan Centrale at 11:55 a.m. and not 11:07, oops. Still, it's a full four hours to try and see the Duomo.

Thank you all for the info, it's very helpful. I think we'll try and see the Duomo and keep our fingers crossed that the line to get our luggage doesn't take too long, but there will probably be lots of people trying to do the same thing we're doing. I'm tempted just to lug it with us and not bother with the luggage hold at Centrale but I'm not a fan of riding the metro with luggage.

Plenty of time for that. I did something similar when I landed in Milan this past summer. I had 5 hours till my train departed. I dropped my bag off and went sighseeing. I headed back to the the station an hour before my train left. Figured that was enough time for the subway and get my bag and it was plenty. It's not that far from Centrele to your other station but since you can't miss that train, keep your depart time at 2:45 to go back. They are connected by the subway incase you want to use that and not the taxi.

Thanks Robert. Yes, I'm hoping an hour and 15 minutes will be enough time to take the metro back to Centrale, pick up our bags, and take a quick taxi over to Garibald. I think the two possible hold ups would be a long line at the luggage hold area or not being able to get a quick taxi and instead having to head back in the station and take the metro. That's what I'm a bit worried about. I know that the laws of time and physics and Murphy demands that, the closer to the time of your train leaving the station, the further away you will be and the slower everyone and every thing will move. (Did that sentence even make sense?) That will certainly eat up stomach lining, LOL.